Vehicle power seat adjusters typically include a flexible shaft for transmitting torque, for example between a motor and an automobile seat to be adjusted. The shaft may include a core including one or more wire layers helically wound in opposite winding directions. The outer layer may include a number of wires with a circular cross-section and sometimes a gap or two. The wires of the outer layer are typically helically wound in a winding direction opposite to that of an adjacent layer. A strand of flocked yarn is typically wound into the gap and protrudes above the adjacent wires of the outer layer. The strand or strands of yarn is typically only used to provide an interference fit, e.g., to prevent rattling, in the shaft tip interfaces.
Moreover, typical power seat actuator systems consist of a long flexible shaft and a short flexible shaft, with formed squares at the ends, both driven by an electric motor in between them. The long flexible shaft is typically supported inside a tubular casing which is fastened to a bracket that also carries the motor, or the shaft is supported by a tunnel integrated into the bracket. The casing constricts the whipping action of the long shaft, and to dampen the vibration of the shaft inside the casing, the shaft is typically covered with a wound layer of “over-flock” or with “electrostatic flocking”. The problem with this configuration is that if the dampening layer is too thick, the friction between shaft and casing is too great, but if it is too thin, it may not be sufficient to prevent resonant vibration. It is difficult to hold this dampening layer within a close tolerance due to the nature of the materials.